Multilingualism in the classroom is one of the many challenges found in the cumbersome bag that the South African education system is carrying over its shoulders at present. Globalisation and migration have added to the burden as factors adding further diversity to the already diverse classroom. In South Africa the spotlight is focused on equality. Equality is expected in the education system, and in the classroom and especially in tests. With 11 official languages excluding the additional languages from foreign learners it has become a daunting task to create tests that are fair across multilingual learners in one classroom. Items in tests that function differently from one group to another can provide biased marks. An investigation was done in order to detect any biased items present in a Picture Vocabulary Test. The study was lead by the main research question being: How do objects used in a Picture Vocabulary Test influence the level of validity? The first sub research question was: How do objects used in a Picture Vocabulary Test influence the level of validity? The next sub question was: To what extent is an undimensional trait measured by a Picture Vocabulary Test? The final subquestion was To what extent do the items in a Picture Vocabulary Test perform the same for the different language groups? This Picture Vocabulary Test was administered to Grade 1 learners in Afrikaans, English or Sepedi speaking schools within Pretoria, Gauteng. The sample totalling 1361 learners. The process involved a statistical procedure known as Rasch analyses. With the help of Rasch a Differential Item Functioning (DIF) analysis was done to investigate whether biased items were present in the test. The aim of this study it is to create greater awareness as to how biased items in tests can be detected and resolved. The results showed that the items in the Picture Vocabulary Test all tested vocabulary. Although items were detected that did indeed perform differently across the three language groups participating in the study.